Suppress warning in zsh_completion script

Suppress warning in zsh_completion script

--- a/contrib/zsh_completion	Thu Sep 29 15:18:32 2005 -0700
+++ b/contrib/zsh_completion	Fri Sep 30 11:06:13 2005 -0700
@@ -16,7 +16,7 @@
 typeset -A opt_args
 local subcmds repos tags newFiles addedFiles
 
-tags=($(hg tags | sed -e 's/[0-9]*:[a-f0-9]\{40\}$//; s/ *$//'))
+tags=($(hg tags 2> /dev/null | sed -e 's/[0-9]*:[a-f0-9]\{40\}$//; s/ *$//
 subcmds=($(hg -v help | sed -e '1,/^list of commands:/d' \
       -e '/^global options:/,$d' -e '/^ [^ ]/!d; s/[,:]//g;'))